I have the same problem as in Gentoo.In order to install gcc 7.3 rc2 I think I would need to be sid.I don't think I want to be sid at present.
CheersMF
Regards
Michael
.-.. .. ...- . .-.. --- -. --. .- -. -.. .--. .-. --- ... .--. . .-.
War isn't a good life, but it's life.
-- Kirk, "A Private Little War", stardate 4211.8